Hydrogen-bond effects on the electronic absorption spectrum and evaluation of nonlinear optical properties of an aminobenzodifuranone derivative that exhibits the largest positive solvatochromism

Abstract

In this work, for the first time, a theoretical approach to describing the influence of hydrogen-bond formation on the electronic absorption spectrum and nonlinear optical properties of an aminobenzodifuranone derivative (ABF) that exhibits the largest positive solvatochromic shift compared to other known chromophores is given. The solvent effect was included via the supermolecule (SM) method. The calculations were performed for a strong low-lying (π→π*) transition based on the configuration interaction singles (CIS) and time-dependent DFT (TDDFT) methods. The first-order hyperpolarizabilities (β) were computed using the finite-field (FF) technique combined with the Hartree–Fock (HF) theory. Reasonable agreement between theory and experiment was obtained for the solvatochromic shifts of the ABF molecule. Moreover, it was found that H-bond formation strongly influences the NLO response of the systems investigated.

Figure The interaction difference-density maps of the systems studied: a II - complex ABF with NFTB; b III - complex ABF with HMPA. The red color designates an increase of the electron density caused by the intermolecular interactions, whereas blue indicates a corresponding decrease of the electron density. The isodensity contours were plotted for ±0.01 electron/bohr3 (DFT/B3LYP/6-31G(d,p)).